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Horizontal gene transfer from Agrobacterium to plants.

Matveeva TV, Lutova LA - Front Plant Sci (2014)

Bottom Line: A similar cT-DNA has also been found in other species of the genus Nicotiana.Thus, the events of T-DNA insertion in the plant genome might have affected their evolution, resulting in the creation of new plant species.In this review we focus on the structure and functions of cT-DNA in Linaria and Nicotiana and discuss their possible evolutionary role.

View Article: PubMed Central - PubMed

Affiliation: Department of Genetics and Biotechnology, St. Petersburg State University St. Petersburg, Russia.

ABSTRACT
Most genetic engineering of plants uses Agrobacterium mediated transformation to introduce novel gene content. In nature, insertion of T-DNA in the plant genome and its subsequent transfer via sexual reproduction has been shown in several species in the genera Nicotiana and Linaria. In these natural examples of horizontal gene transfer from Agrobacterium to plants, the T-DNA donor is assumed to be a mikimopine strain of A. rhizogenes. A sequence homologous to the T-DNA of the Ri plasmid of Agrobacterium rhizogenes was found in the genome of untransformed Nicotiana glauca about 30 years ago, and was named "cellular T-DNA" (cT-DNA). It represents an imperfect inverted repeat and contains homologs of several T-DNA oncogenes (NgrolB, NgrolC, NgORF13, NgORF14) and an opine synthesis gene (Ngmis). A similar cT-DNA has also been found in other species of the genus Nicotiana. These presumably ancient homologs of T-DNA genes are still expressed, indicating that they may play a role in the evolution of these plants. Recently T-DNA has been detected and characterized in Linaria vulgaris and L. dalmatica. In Linaria vulgaris the cT-DNA is present in two copies and organized as a tandem imperfect direct repeat, containing LvORF2, LvORF3, LvORF8, LvrolA, LvrolB, LvrolC, LvORF13, LvORF14, and the Lvmis genes. All L. vulgaris and L. dalmatica plants screened contained the same T-DNA oncogenes and the mis gene. Evidence suggests that there were several independent T-DNA integration events into the genomes of these plant genera. We speculate that ancient plants transformed by A. rhizogenes might have acquired a selective advantage in competition with the parental species. Thus, the events of T-DNA insertion in the plant genome might have affected their evolution, resulting in the creation of new plant species. In this review we focus on the structure and functions of cT-DNA in Linaria and Nicotiana and discuss their possible evolutionary role.

No MeSH data available.


Related in: MedlinePlus

Structure of cT-DNA in the Nicotiana glauca genome (based on Suzuki et al., 2002). The cT-DNA and its flanking regions are indicated. Lines with a single arrowhead indicate the imperfect inverted repeat. Lines with arrowheads at both ends indicate regions sequenced by each of three groups.
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Figure 1: Structure of cT-DNA in the Nicotiana glauca genome (based on Suzuki et al., 2002). The cT-DNA and its flanking regions are indicated. Lines with a single arrowhead indicate the imperfect inverted repeat. Lines with arrowheads at both ends indicate regions sequenced by each of three groups.

Mentions: In 2001 Suzuki et al. characterized A. rhizogenes strain MAFF301724 and described a new opine synthase gene (mikimopine synthase gene mis). A part of the mis gene displayed strong homology to distal fragments of N. glauca cT-DNA, called NgmisL and NgmisR, respectively (Suzuki et al., 2002). Suzuki et al. (2002) suggested that the complete cT-DNA region of N.glauca is comprised of the 7968 bp left arm and 5778 bp right arm that were derived from the T-DNA of a mikimopine Ri plasmid similar to pRi1724. The level of nucleotide sequence similarity between the left and right arms is greater than 96% and the gene order is conserved suggesting a duplication event. The structure of the N.glauca cT-DNA is summarized in Figure 1. Since cT-DNA has been identified in all studied varieties of N. glauca (Furner et al., 1986), it is reasonable to suggest that the transformation event occurred before the formation of this species. This suggests that other related species may contain cT-DNA.


Horizontal gene transfer from Agrobacterium to plants.

Matveeva TV, Lutova LA - Front Plant Sci (2014)

Structure of cT-DNA in the Nicotiana glauca genome (based on Suzuki et al., 2002). The cT-DNA and its flanking regions are indicated. Lines with a single arrowhead indicate the imperfect inverted repeat. Lines with arrowheads at both ends indicate regions sequenced by each of three groups.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4127661&req=5

Figure 1: Structure of cT-DNA in the Nicotiana glauca genome (based on Suzuki et al., 2002). The cT-DNA and its flanking regions are indicated. Lines with a single arrowhead indicate the imperfect inverted repeat. Lines with arrowheads at both ends indicate regions sequenced by each of three groups.
Mentions: In 2001 Suzuki et al. characterized A. rhizogenes strain MAFF301724 and described a new opine synthase gene (mikimopine synthase gene mis). A part of the mis gene displayed strong homology to distal fragments of N. glauca cT-DNA, called NgmisL and NgmisR, respectively (Suzuki et al., 2002). Suzuki et al. (2002) suggested that the complete cT-DNA region of N.glauca is comprised of the 7968 bp left arm and 5778 bp right arm that were derived from the T-DNA of a mikimopine Ri plasmid similar to pRi1724. The level of nucleotide sequence similarity between the left and right arms is greater than 96% and the gene order is conserved suggesting a duplication event. The structure of the N.glauca cT-DNA is summarized in Figure 1. Since cT-DNA has been identified in all studied varieties of N. glauca (Furner et al., 1986), it is reasonable to suggest that the transformation event occurred before the formation of this species. This suggests that other related species may contain cT-DNA.

Bottom Line: A similar cT-DNA has also been found in other species of the genus Nicotiana.Thus, the events of T-DNA insertion in the plant genome might have affected their evolution, resulting in the creation of new plant species.In this review we focus on the structure and functions of cT-DNA in Linaria and Nicotiana and discuss their possible evolutionary role.

View Article: PubMed Central - PubMed

Affiliation: Department of Genetics and Biotechnology, St. Petersburg State University St. Petersburg, Russia.

ABSTRACT
Most genetic engineering of plants uses Agrobacterium mediated transformation to introduce novel gene content. In nature, insertion of T-DNA in the plant genome and its subsequent transfer via sexual reproduction has been shown in several species in the genera Nicotiana and Linaria. In these natural examples of horizontal gene transfer from Agrobacterium to plants, the T-DNA donor is assumed to be a mikimopine strain of A. rhizogenes. A sequence homologous to the T-DNA of the Ri plasmid of Agrobacterium rhizogenes was found in the genome of untransformed Nicotiana glauca about 30 years ago, and was named "cellular T-DNA" (cT-DNA). It represents an imperfect inverted repeat and contains homologs of several T-DNA oncogenes (NgrolB, NgrolC, NgORF13, NgORF14) and an opine synthesis gene (Ngmis). A similar cT-DNA has also been found in other species of the genus Nicotiana. These presumably ancient homologs of T-DNA genes are still expressed, indicating that they may play a role in the evolution of these plants. Recently T-DNA has been detected and characterized in Linaria vulgaris and L. dalmatica. In Linaria vulgaris the cT-DNA is present in two copies and organized as a tandem imperfect direct repeat, containing LvORF2, LvORF3, LvORF8, LvrolA, LvrolB, LvrolC, LvORF13, LvORF14, and the Lvmis genes. All L. vulgaris and L. dalmatica plants screened contained the same T-DNA oncogenes and the mis gene. Evidence suggests that there were several independent T-DNA integration events into the genomes of these plant genera. We speculate that ancient plants transformed by A. rhizogenes might have acquired a selective advantage in competition with the parental species. Thus, the events of T-DNA insertion in the plant genome might have affected their evolution, resulting in the creation of new plant species. In this review we focus on the structure and functions of cT-DNA in Linaria and Nicotiana and discuss their possible evolutionary role.

No MeSH data available.


Related in: MedlinePlus